My coolant has been getting low for some time now, but my bus-A/C is still working [for now]

I have tried a few places to get it topped-up, but no one will touch it until we can figure out what type of refrigerant is in it.

I have been told that if it is the old type then I must do a system up-grade. [or get it topped up in Mexico... :-) ]If it is the new type then it must be confirmed some how to avoid mixing and causing damage.

Does anyone know how one tells what kind of refrigerant is in a system... Are there test that can be done.

All service records I have and calls to the previous owner have produced no clues.

Steve, generally a sticker is attached either near the original toilet dump or inside the rear engine doors that says '134', etc. I don't know about a test for the actual freon. However, R12 (original) and R134 systems have different size fittings where you add freon. You might find someone who has R134 equipment and see if it fits the fittings. Darren

More...I got tired of paying someone to top off my MC9 bus air. I was getting charged a service fee plus $20 a pound for R134. I went to the local auto parts store and bought the manifold and guages for about $60. Then I went to SAM's warehouse club for the Freon. A 30 pound bottle was $180. It doesn't take much to learn how to read the guages.

Your MC9 system holds a lot of freon!!! When it gets too low, the clutch on your compressor will stop engaging. Then you'll have to pull a vacuum to be able to add freon at all. Catch it while you can! A good way to look for leaks is check your hoses and fittings for dirt. A leak will leave the outside of the hose or fitting kinda oily and dust will accumulate at that point.

I had my system pressure tested for leaks, something they said they had to do before they even consider adding anything.

I like your suggestion about getting the gages and topping up myself and I'll do that as soon as I can figure out for sure what type of freon I have. I was also told that all hoses had to be replaced if converting from R12 to R134. I didn't know about the different size fittings for each type, but that would make sense so as to prevent accidental mixing of the two types.

My bus never had a factory toilet [it was a 49 passenger coach] but I will check to see if there is any sticker in the engine compartment, but I don't recall seeing any.

Almost any GOOID size A/C shop will have an "A/C gas analysis unit" - a fairly expenseive unit that tell them exactly what type refrigerant is in a system or bottle - r-12 / r-134 / after market propane mix

They tested a bottle of r-12 I purchased over via ebay for free - what a deal r-12 20lbs bottle (small) full for $12 (yep $12) - it took a year to slowly transport the bottle from California to Florida - via a classic GMC club I belong to

Almost any GOOID size A/C shop will have an "A/C gas analysis unit" - a fairly expenseive unit that tell them exactly what type refrigerant is in a system or bottle - r-12 / r-134 / after market propane mix

They tested a bottle of r-12 I purchased over via ebay for free - what a deal r-12 20lbs bottle (small) full for $12 (yep $12) - it took a year to slowly transport the bottle from California to Florida - via a classic GMC club I belong to

Pete RTS/Daytona

Thanks Pete...

I was also told that R12 was prohibited and that no service shop was allowed to use it any more.... This might be a country specific thing, Not sure on the U.S. laws, Canada says no way and like always, in Mexico, you can get anything done...

Have you encounter any regulations to that effect or is the info I was given wrong...?

Steve, I'm not sure that R12 is illegal, its just more trouble to handle so shops don't like to. When working on an R12 system, the shop has to recover all the gas and not let it leak into the atmosphere. Then they have to dispose of it if not putting it back into the system. I'm certainly not advising it ;) ;) but some people just let it go like we did 25 years ago.

Your toilet dump would have been in the curbside engine compartment. You can sometimes get to parts of your compressor easier through this door. The R134 sticker may be there. Since you mentioned hoses, the R134 ones are different and that may be evidence of a conversion. However, I've seen the old hoses left on after conversions so that's not a sure-fire method.

the r-12 has screw on fittings, the 134 has a quick connect, all you need to do is look at it, you can fill it yourself witha kit from any auto parts, the r-12 is not illegal but has to be serviced by licenced teck and recovered (politics) you can buy the cans of 134 anywhere as well, but if you have a leak you need to fix it as it will be a pain filling it all the time, i pulled mine out of my 06 and trashed it, put in a couple of street rod units and havent had to add a thing to the system since. R-12 is very expensive and hard to get, not sure the current price , if you got that id change it over and get the leak fixed at the same time. There is nobody that will sell you r-12 unless you are licenced. i still have some around from the old days. Frank allen4106

the r-12 has screw on fittings, the 134 has a quick connect, all you need to do is look at it, you can fill it yourself witha kit from any auto parts, the r-12 is not illegal but has to be serviced by licenced teck and recovered (politics) you can buy the cans of 134 anywhere as well, but if you have a leak you need to fix it as it will be a pain filling it all the time, i pulled mine out of my 06 and trashed it, put in a couple of street rod units and havent had to add a thing to the system since. R-12 is very expensive and hard to get, not sure the current price , if you got that id change it over and get the leak fixed at the same time. There is nobody that will sell you r-12 unless you are licenced. i still have some around from the old days. Frank allen4106

Street rod units are add-on air conditioners for older cars from the 50s and 60s that have generally been restored.

See www.hotrodair.com or www.vintageair.com for some examples. I have no idea how multiples of these could be put in a bus. If I was going this route I would probably get the auxiliary air conditioning units from Welch industries designed for a bus.

Street rod units are add-on air conditioners for older cars from the 50s and 60s that have generally been restored.

See www.hotrodair.com or www.vintageair.com for some examples. I have no idea how multiples of these could be put in a bus. If I was going this route I would probably get the auxiliary air conditioning units from Welch industries designed for a bus.

My 2 cents: My MC9, a NJT serviced coach lost coolant over the winters, a little more each year until this past winter, system empty. Inspection revealed leak'n low pres. hose at compressor. Went to local hose co., ordered both low and high pres. hoses. My coach was converted to R134A before i purchased it, all new hoses and compressor. I buy refrigerant in 30#s and the price over the last couple of years have climbed quite a bit. I went with ENVIRO-SAFE (industrial) 36#. $159.00. So far so good and very cold. I have also used FREEZE-12 in other vehicles and no problems, also cost less than R134A. Forget about R12, it's available, the last i saw was about $1200.00 for 30#s.

Steve, they are after market add on a/c units that produce 22500 btu s each, i have two, they look like toys and some think they couldnt do the job, they use 13000 btu roof tops and think thats fine but my 22500 are not big enough according to some, but when we go down the road in the Texas summer and its 74 deg in the front driver seat i could care less. thats the way it works and many times we only run one. they have done a great job for us>, there are about 20 or so others out there with thesame setup, and ive heard no complaints yetFrank Allen4106

Steve, they are after market add on a/c units that produce 22500 btu s each, i have two, they look like toys and some think they couldnt do the job, they use 13000 btu roof tops and think thats fine but my 22500 are not big enough according to some, but when we go down the road in the Texas summer and its 74 deg in the front driver seat i could care less. thats the way it works and many times we only run one. they have done a great job for us>, there are about 20 or so others out there with thesame setup, and ive heard no complaints yetFrank Allen4106

Frank,

Any brand names or links?

I have two roof airs, but want to put air up under the dash where the original unit was.

Cliff i bought everthing i needed from rainbow products near charlotte NC, the mans name is Mike Brown, i have twp units , you may need three because of the added size, our bus is 35 ft, he will have everthing uou need except compresser mounting brackets, i run two units and a single compresser, have a small condenser over the bottom of the radiator, these units are small which makes them easier to install, i have no connection to thei guy or his company just passing on info, i also have one of these units in my 55 olds and it will freeze you out of there on any given day. the big thing with the bus is getting air in the front where the driver sits , and it does that well. the ph nimber is 704-278 0054 will post a web site that details my system that a frend put on for me if you care to lookFrank allen

cliff, wonder where you are in fla?? i get down there a lot, was born there and lived there many yrs, have family still living there, anyway here is the web site on my systemhttp://users.myelcel.com/roncarter/splitsystem/ my son and myself put this system on in one day, take a look and see what you think. we dont even use the roof air on the road, no needFrank allen4106

Cliff i bought everthing i needed from rainbow products near charlotte NC, the mans name is Mike Brown, i have twp units , you may need three because of the added size, our bus is 35 ft, he will have everthing uou need except compresser mounting brackets, i run two units and a single compresser, have a small condenser over the bottom of the radiator, these units are small

What BTU size is the compressor and condensor to handle a 35 foot coach? By the time I bought something big enough for a 43 foot coach I would probably be just as well off with the original system I suppose.

The compressers dont have btu ratings, all it is is a pump anyway, and you dont need no great big thing in your bus unless you are going to have 40 or 50 people in there producing heat, the condenser is small also, mine is called a space saver, has extra rows of tubes but is small in size. ive seen buses run the original a/c system with a automotive compresser, as i said dont need that huge thing they had in there. Frank Allen

Your toilet dump would have been in the curbside engine compartment. You can sometimes get to parts of your compressor easier through this door. The R134 sticker may be there. Since you mentioned hoses, the R134 ones are different and that may be evidence of a conversion. However, I've seen the old hoses left on after conversions so that's not a sure-fire method.

Darren

I just inspected that compartment and the unit a little closer, No stickers anywhere, some steel braided lines, not sure where to find out if the "connections" are screw-on or quick-fit, as KingFa mentioned.

Go into the condencer compartment, and look for the expantion valve, [sort of valve look with liquid lines going in and out with a small capilary tube on top] it mayalso be in with the evaporator coil. you may have to remove the inspection cover. On the expantion valve may be printing of which refrigerant may be in the system.If not, you could read me the mo. # of the valve and I can cross ref. it to the refrigerant it was designed for!

Go into the condencer compartment, and look for the expantion valve, [sort of valve look with liquid lines going in and out with a small capilary tube on top] it mayalso be in with the evaporator coil. you may have to remove the inspection cover. On the expantion valve may be printing of which refrigerant may be in the system.If not, you could read me the mo. # of the valve and I can cross ref. it to the refrigerant it was designed for!

Hope this will help!

Nick-

Sounds good Nick...

I'll get in there first thing in the morning and let you know what I find.

But, that still is not complete proof. I've seen alot of retrofits that did'nt change the porting. especially early on in the late 80's!

I would still like to see the TX valve Steve.

Nick-

I didn't forget Nick...I'll give you that info in the morningBut it looks like an up-grade so far...I'm not about to chase R12 around the planet... ;-)Might as well do the up-grade and it's one less thing to worry about.

I'll try to post some photos for you of that compartment when I get in there also.

AT THE VERY LEAST - THIS IS VERY IMPORTANT INFO FOR NEW PROSPECTIVE BUS OWNERS TO CHECK OUT THOROUGHLY ON ANY OLDER UNIT THEY MAY BE LOOKING AT - COST TO UP-GRADE COULD RUN A FEW THOUSAND

Weather it's R-12 or not, dosn't matter to me! I won't let you buy R-12 if you were my worst enemy!!The current market price for R-12 is 1544.00 30lb can. Being in the commercial refrigeration biz. since I was dragged at along by my father at the age of 13,[no kid wants to work at 13]I think I learned something, mabe enough to get me in trouble. Well with that said, I can only tell you that I have direct drop in refrigerants that replace R-12systems using polyester oil. Now I am in no way telling you to try anything other than what your system calls for. I am only telling you that in the commercial refrigeration biz I use upward of 30 different blends of refrigerent!

I still have Bus-Air, for now... [Remember, my Freon is getting very low] but if someone was in a similar situation, I think it is possible to run at least one roof-top-air off of the bus alternator. Someone correct me if I am wrong, but the power drain [in amp load] placed on the alternator to drive that monster condenser fan is more strain than the 15 or so amps of a roof-top.

If this is correct, and I think it is... then one roof-top operated this way may get you buy, [cooling wise] as we are not on the road that long, compared to all the sitting around we do at campsites or at home. I guess running the desert would be a bit challenging.

There maybe a fuel savings here too, to just rip out that entire Bus-Air system altogether. It must weigh a ton!

Total cost savings [including add fuel savings due to reduced bus weight - not to mention a great space left over for a geny or something] in ripping out the entire Bus-Air with an alternate method of cooling your rig down while underway, compared to up-grading to the new R134 A solar panel or three could even be used to kick in the second roof-top on sunny days when you need it the most.

I kept my bus air, because I had tried that about 8 yrs ago on one of my service vans that had no A/C. We installed a 13,500 Duotherm on the roof, added a 2000wstate power inverter, and a 8D battery [6.2L diesel engine in van] 1st problem, while driving the duotherm did very little cooling. Reason, lots of heat gain/ cool loss due to air leaks. [freeze your a** off at red lights]2nd problem, The amp draw off the inverter caused the 8D to drain in 20 min. and the 110 amp. alt. in the van couldn't keep up!

My bus air only has to run 10 to 15 min's to cool the coach, than only 5 min at a time to maintain it. not much load on the DD!

I kept my bus air, because I had tried that about 8 yrs ago on one of my service vans that had no A/C. We installed a 13,500 Duotherm on the roof, added a 2000wstate power inverter, and a 8D battery [6.2L diesel engine in van] 1st problem, while driving the duotherm did very little cooling. Reason, lots of heat gain/ cool loss due to air leaks. [freeze your a** off at red lights]2nd problem, The amp draw off the inverter caused the 8D to drain in 20 min. and the 110 amp. alt. in the van couldn't keep up!

My bus air only has to run 10 to 15 min's to cool the coach, than only 5 min at a time to maintain it. not much load on the DD!

Nick-

I hear ya...

I'm running a 4024 computer controlled Trace using the WinVerter program with 8 - 8Ds [4 banks of 24vdc] as storage, plus the two bus bats linked through a 24vdc continuous duty solenoid whenever I need to join everything together or to receive power from the engine alternator to replenish the 8 - 8Ds house bats while under way.

I want to get into solar/wind as one of my next pet project upgrades anyways... maybe sooner than I planed due to this A/C issue and the current fuel and campside electrical cost that's the reason I went for such a heavy electrical system durring initial conversion

This may give me a little head start with considering an alternate to Bus-Air cooling now that it seems I am possibly facing big bucks in up-grading to R134... I could put that money to better use in Solar and Wind as I have everything else in place already.

Steve still got my # ? I got a guy about 35 minutes from me, on the way in iif you were coming up from TX, who is the BEST there is with A/C in coach with the road air still intact! He's an older hand that I've learned alot from, we used to drive 120 miles to Memphis to have him work on our stuff but he's relocated closer to us and now people from Memphis drive up to his new location to have work done, if it were me I'd stop in and chat with him and see what he has to say towards fixing or doing away with what ya got! He's in a direct rte up to me coming up 51 outta Memphis toward my place! Just my 2 cents worth which these days that and $2.98 will buy you a gallon of fuel! LOL!

Your first pic. top dead center, Thats the expantion Valve! [thormo expantion valve or TX for short] Look for stamped #'s or print.

On your 2nd pic I see the WHITE reciever tank that is used for R-12, [still dosen't confirm] and the main story I see is all your fittings are well established in corrosion. Looks to me like the system is orriginal R-12!

Let me know if you see anything on the TX.

Nick-

I guess I'm lucky the system is even working at all. Both red indicators on the white tank are both at the bottom, I take it that means almost empty. Corrosion on all the fittings and the system appears that it has never been touched in years.

I had the bus out for a run, just got back, and the air is still working, very cold, even in this 95 degree Texas heat here.

I'll go out and check for any info on that TX for you and will let you know what I find, if anything.